Topic Area: 12a. Biotechnology for Sustainable Mining

Formatted Title:

Demonstrating Selective Gangue Removal from Nickel Sulfide Concentrate in a Continuous Pilot Unit

Background/Objectives:

In most mining applications, huge volumes of waste material are generated due to the large scale and small percentage of value metal in the ore being mined. As we strive to improve the sustainability of mining through biologically inspired innovations, we look for opportunities to use what is currently waste in conventional processes to generate value and decrease the overall energy usage in mineral processing while reducing waste. The effective removal of gangue (e.g., waste minerals) from the valuable minerals is the primary requirement for all mining operations at every step and at every scale. Therefore, we set out to utilize a unique blend of microbially-produced bio-solvents to selectively solubilize gangue minerals. We targeted the removal of magnesium-bearing minerals from a nickel sulfide concentrate where the elevated Mg content reduces slag viscosity and hinders nickel smelter operations.

Approach/Activities:

Allonnia has developed a continuous process to remove gangue from nickel sulfide concentrate that has the potential to significantly decrease energy usage in mineral processing and smelting. The process includes three essential steps to selectively remove magnesium-bearing minerals from nickel sulfide concentrate to upgrade the nickel grade and reduce the magnesium burden on slag formation: (1) an agitated leach, (2) a solid-liquid separation, and (3) a bio-solvent regeneration step. The gangue elements are removed from the bio-solvent and directed into potential new value streams (such as MgO production), while regenerating the bio-solvent for continued use. We envision that our simple process flow can be used as a bolt-on process as part of an existing operation and add value by treating only a side stream of material. Demonstrating the ability of the bio-solvent process to operate continuously is an essential step toward commercialization. Prior to testing the process in continuous operations, each step was tested in laboratory batch tests. When batch testing was successful, a laboratory model of the continuous process was built to demonstrate that it can be operated as a treatment train with actual nickel concentrate to the point of approaching equilibrium. Demonstration of the continuous process operating 24 hours per day for five days is currently underway.

Troy Bednarski

Affiliation

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(Group 2, Poster Board #46) Demonstrating Selective Gangue Removal from Nickel Sulfide Concentrate in a Continuous Pilot Unit